#include <lcd.h>
#include <delay.h>

static void lcd_port_clear(void)
{
	LCD_DPORT->ODR &= ~(LCD_E_MASK);
	LCD_DPORT->ODR &= ~(LCD_DATA_MASK | LCD_RS_MASK | LCD_E_MASK);
}

static void lcd_enable(void)
{
	__ASM("nop");
	__ASM("nop");
	__ASM("nop");
	LCD_DPORT->ODR |= LCD_E_MASK;
	__ASM("nop");
	__ASM("nop");
	__ASM("nop");
	__ASM("nop");
	__ASM("nop");
	__ASM("nop");
	LCD_DPORT->ODR &= ~LCD_E_MASK;
	__ASM("nop");
	__ASM("nop");
	__ASM("nop");
	__ASM("nop");
	__ASM("nop");
	__ASM("nop");
}

static void lcd_out(uint8_t data)
{
	LCD_DPORT->ODR &= ~(LCD_DATA_MASK);
	LCD_DPORT->ODR |= (data << LCD_DATA_BIT_OFFSET) & LCD_DATA_MASK;
}

static void lcd_data(uint8_t data)
{
	lcd_port_clear();
	LCD_DPORT->ODR |= LCD_RS_MASK;
	lcd_out((data>>4) & 0xFU);
	lcd_enable();
	lcd_out(data & 0xFU);
	lcd_enable();
	delay_ms(1);
}

static void lcd_command(uint8_t data)
{
	lcd_port_clear();
	lcd_out((data>>4) & 0xFU);
	lcd_enable();
	lcd_out(data & 0xFU);
	lcd_enable();
	delay_ms(1);
}

#define LCD_DDADR_LINE1         0x00
#define LCD_DDADR_LINE2         0x40
#define LCD_DDADR_LINE3         0x10
#define LCD_DDADR_LINE4         0x50

// Clear Display -------------- 0b00000001
#define LCD_CLEAR_DISPLAY       0x01

// Cursor Home ---------------- 0b0000001x
#define LCD_CURSOR_HOME         0x02

// Set Entry Mode ------------- 0b000001xx
#define LCD_SET_ENTRY           0x04

#define LCD_ENTRY_DECREASE      0x00
#define LCD_ENTRY_INCREASE      0x02
#define LCD_ENTRY_NOSHIFT       0x00
#define LCD_ENTRY_SHIFT         0x01

// Set Display ---------------- 0b00001xxx
#define LCD_SET_DISPLAY         0x08

#define LCD_DISPLAY_OFF         0x00
#define LCD_DISPLAY_ON          0x04
#define LCD_CURSOR_OFF          0x00
#define LCD_CURSOR_ON           0x02
#define LCD_BLINKING_OFF        0x00
#define LCD_BLINKING_ON         0x01

// Set Shift ------------------ 0b0001xxxx
#define LCD_SET_SHIFT           0x10

#define LCD_CURSOR_MOVE         0x00
#define LCD_DISPLAY_SHIFT       0x08
#define LCD_SHIFT_LEFT          0x00
#define LCD_SHIFT_RIGHT         0x04

// Set Function --------------- 0b001xxxxx
#define LCD_SET_FUNCTION        0x20

#define LCD_FUNCTION_4BIT       0x00
#define LCD_FUNCTION_8BIT       0x10
#define LCD_FUNCTION_1LINE      0x00
#define LCD_FUNCTION_2LINE      0x08
#define LCD_FUNCTION_5X7        0x00
#define LCD_FUNCTION_5X10       0x04

#define LCD_SOFT_RESET          0x30

// Set CG RAM Address --------- 0b01xxxxxx  (Character Generator RAM)
#define LCD_SET_CGADR           0x40

#define LCD_GC_CHAR0            0
#define LCD_GC_CHAR1            1
#define LCD_GC_CHAR2            2
#define LCD_GC_CHAR3            3
#define LCD_GC_CHAR4            4
#define LCD_GC_CHAR5            5
#define LCD_GC_CHAR6            6
#define LCD_GC_CHAR7            7

// Set DD RAM Address --------- 0b1xxxxxxx  (Display Data RAM)
#define LCD_SET_DDADR           0x80

void lcd_clear(void)
{
	lcd_command(LCD_CLEAR_DISPLAY);
	delay_ms(3);
}

void lcd_home( void )
{
	lcd_command(LCD_CURSOR_HOME);
	delay_ms(3);
}

void lcd_setcursor( uint8_t x, uint8_t y )
{
	uint8_t data;

	switch (y)
	{
	case 0:    // 1. Zeile
		data = LCD_SET_DDADR + LCD_DDADR_LINE1 + x;
		break;

	case 1:    // 2. Zeile
		data = LCD_SET_DDADR + LCD_DDADR_LINE2 + x;
		break;

	case 2:    // 3. Zeile
		data = LCD_SET_DDADR + LCD_DDADR_LINE3 + x;
		break;

	case 3:    // 4. Zeile
		data = LCD_SET_DDADR + LCD_DDADR_LINE4 + x;
		break;

	default:
		return;                                   // für den Fall einer falschen Zeile
	}

	lcd_command(data);
}

void lcd_string(const char *data)
{
	while(*data != '\0') {
		lcd_data((uint8_t)*data++);
	}
}

void lcd_init(void)
{
	int i;

	lcd_port_clear();
	delay_ms(100);
	LCD_DPORT->ODR |= (0x3 << LCD_DATA_BIT_OFFSET);

	for (i = 0; i < 3; i++) {
		lcd_enable();
		delay_ms(5);
	}

	// Set 4 Bit mode
	lcd_port_clear();
	LCD_DPORT->ODR |= (0x2<<LCD_DATA_BIT_OFFSET);
	lcd_enable();
	delay_ms(2);

	// 4-bit Modus / 2 Zeilen / 5x7
	lcd_command( LCD_SET_FUNCTION |
		     LCD_FUNCTION_4BIT |
		     LCD_FUNCTION_2LINE |
		     LCD_FUNCTION_5X7 );

	// Display ein / Cursor aus / Blinken aus
	lcd_command( LCD_SET_DISPLAY |
		     LCD_DISPLAY_ON |
		     LCD_CURSOR_OFF |
		     LCD_BLINKING_OFF);

	// Cursor inkrement / kein Scrollen
	lcd_command( LCD_SET_ENTRY |
		     LCD_ENTRY_INCREASE |
		     LCD_ENTRY_NOSHIFT );

	lcd_clear();
}